Blackjack

Chris Buchanan - UNT Integrative Studies Major

I am sitting on a cement bench in front of the Environmental Science building, observing the habitat of a very large blackjack oak tree (Quercus marilandica) on a cold and cloudy afternoon in early February. I am observing the geographical location where the oak tree exists. The blackjack is a small, deciduous, tree that grows up to fifteen meters tall. They can grow in poor, thin, rocky, dry, or sandy soils where few other woody plants can survive. It is a very durable tree that is effective at growing in many conditions. The tree is rooted in a ten by fifteen yard patch of soil that is enclosed by a wall of concrete slabs. The soil is covered by pieces of bark, mulch, fallen leaves, acorns, twigs, and a few, but sparse clumps of grass, and weeds. There are three smaller trees growing beside it. One of which is growing at an odd angle. This much smaller tree is growing at an outward angle, rather than up. It does not have many branches on it and it appears to have been pruned on a regular basis. Human interaction has likely had a dramatic impact on the development of the tree and ultimately, its appearance.

Oak leaves (with an Asian pear leaf, lower left, for comparison). 

The blackjack leaf is to the upper left, center upper is a post oak

leaf, center lower is a red oak leaf, with a bur oak leaf to the right.

I gathered several of the blackjack’s fallen leaves and observed them closely. They are clearly different than the other leaves from the surrounding smaller trees. Unlike the other leaves, the blackjack’s leaves are long and broad, as well as more rounded in shape. They have a tapered base that extends to a broad three-lobed bell shape with shallow indentions while the other leaves have more pointed tips extending from their sides. The oak’s leaves are darker in color and have well-defined stems and veins that cover the leaf like arteries throughout a human body. 

Next to the oak sits a small pond. The pond has a fountain in the center that is composed of various types of rocks that are stacked on top of each other. Growing out of the rocks are tall and thin branches that are almost entirely barren of leaves. Dead leaves float lifelessly on the surface of the pool. The pond is surrounded by numerous stone tiles and cement slabs that form its’ wall. The pond is the habitat of several forms of life that exist together in the environment that it creates. One such life form is the Gambusia fish. The Gambusia fish is commonly known as the mosquito fish because it feeds on the larvae of mosquitos. This is the Gambusia’s niche. It is a small fish that is rarely over 2 inches long and is abundant in the southern United States. The pond is also home to aquatic plants that grow and extend upwards out of the water. These are cattail plants. Cattails are the primary plants in wetlands around the world, growing in water from ¼ inch to 36 inches deep. They and other marsh plants remove excess nutrients and chemicals from the water. This is their niche. Because of this, water leaving a wetland has fewer pollutants than water entering. Scientists believe human-made wetlands can filter pollution better and cheaper than traditional methods. This is an example of the importance and value that increased ecological understanding can have on the way that we relate to our environment.